Film retaining apparatus

ABSTRACT

A camera of the self-developing type including processing rollers for engaging and advancing a film unit along a film exit plane while distributing processing fluid contained therein over an image-forming area of the film unit. A film supporting member is mounted outboard of the rollers for engaging and releasably supporting the exposed film unit along lateral margins thereof as the film unit is advanced from the bite of the rollers.

United States Patent Paglia 1 51 3,688,667 1451 Sept. 5, 1972 [54] FILMRETAINING APPARATUS [72] Inventor: Richard Paglia, Carlisle, Mass.

[73] Assignee: Polaroid Corporation,

bridge, Mass.

[22] Filed: Jan. 4, 1971 [21] Appl. No.: 103,391

Cam-

52 U.S. c1. ..95/13 51 1111. c1. ..G03b 17/52 581 FieldofSearch ..95/13,19,22

[56] References Cited UNITED STATES PATENTS 3,545,357 12/1970Erlichman.. ..-.9s/13 3,016,175 1/1962 7 Warehametal....; ..95/13x3,087,399 4/1963 Fairbank ..95/ 13 X Eloranta et a1. ..95/1 3 Wareham..95/1 3 Primary Examiner-Samuel S. Matthews Assistant Examiner-Alan A.Mathews Attorney-Brown & Mikulka, Lawrence G. Norris and Alfred E.Corrigan v ABSIRACT A camera of the self-developing type includingprocessing rollers for engaging and advancing a film unit along a filmexit plane while distributing processing fluid contained therein over animageforming area of the film unit. A film supporting member is mountedoutboard of the rollers for engaging and releasably supporting theexposed film unit along lateral margins thereof as the film unit isadvanced from the bite of the rollers.

13 Claims, 9 Drawing Figures PAIE'NTEDSEP 5 m2 SHEET 1 0F 3 A? TORNE YSI PATENTEDSEP um 3.688.667

' SHEET 2 BF 3 INVENTOR. RICHARD PAGLIA Mann and WM ATTORNEYS FILMRETAINING APPARATUS BACKGROUND OF THE INVENTION adapted to automaticallyexpose and process a film unit generally include; a chamber forreceiving and supporting a film container, preloaded with a plurality offilm units, in position to locate one film unit contained therein at anexposure plane; an optical and exposure control system for exposing thefilm unit at the exposure plane; means for processing the exposed filmunit while advancing it toward the exterior of the camera; and means forengaging the advancing film unit to releasably retain it on the camerauntil it is manually removed at the convenience of the operator.

The individual film units generally include a photosensitive element, asuperposed transparent image-receiving element, a rupturable podcontaining a viscous processing fluid joined to the two elements at aleading end of the film unit, a processing fluid trap located at atrailing end of the film unit and an opaque binding member for securingthe photosensitive element and the image-receiving element inface-to-face relation and providing opaque peripheral margins on thetransparent image-receiving element which define the bounds of asubstantially rectangular image-forming area. The film unit ispositioned at the exposure plane within the camera with the transparentimagereceiving element facing toward the optical system so that theunderlying photosensitive element may be exposed by actinic lightpassing through the transparent image-receiving element within thebounds of the image-forming area. After exposure, the film unit isadvanced by any suitable film advancing apparatus, leading end first,into engagement with processing means; i.e., pressure-applying members.The pressure-applying members may take the form of a pair of juxtaposedpressure-applying rollers of which one or both are adapted to be powerdriven in a direction to advance the engaged film unit therebetweenalong a film exit plane toward the exterior of the camera and intoengagement with a film retainer located on the exit side of the rollers.Compressive pressure is applied to the film unit as it passes betweenthe rollers, causing the fluid containing pod at the leading end thereofto rupture, thereby releasing a viscous processing fluid which is thenspread in a thin uniform layer between and in contact with thephotosensitive element and the imagereceiving element with any excessprocessing fluid being deposited and retained in the fluid trap at thetrailing end of the film unit. The chemical reaction between theprocessing fluid and the exposed photosensitive element initiates adiffusion transfer process which results in the formation of a positiveimage of the scene photographed which may be viewed through thetransparent image-receiving element.

The camera is adapted to advance the exposed film unit through thepressure-applying rollers in slightly more than one-half of a second.The thin layer of viscous processing fluid spread between thephotosensitive and image-receiving elements requires a short periodoftime to attain a degree of dimensional stability to the extent that itresists physical deformation,

when subjected to additional pressure. Therefore, it is preferred thatadditional pressure not be applied to the image-forming area of the filmunit until the processing fluid has become dimensionally stable sincethe added pressure may cause misalignment of the two elements, therebyresulting in a distorted or an incomplete positive image.

US. Pat. No. 3,545,357 discloses a camera of the self-developing typewhich is adapted to automatically expose and process a film unit in muchthe same manner as described above. Two plates, laterally dimensioned toequal the width of the film unit, are mounted on the exit side of theprocessing rollers for engaging and releasably retaining a film unit onthe camera. An upper plate is fixedly mounted on the camera structureand has a leading edge extending forwardly of the pressure-applyingrollers and located so as to be parallel to and slightly above the bitebetween the pressure-applying rollers. A lower plate, coupled to amechanism for advancing an exposed film unit into engagement with therollers, is pivotally mounted for movement between a first position inwhich the plate is closely adjacent the pressure-applying rollers and inclosing relation to the bite between the rollers, and a second position,extending forwardly of the pressureapplying rollers in which a leadingedge of the lower plate is located parallel with and slightly below thebite of the rollers where it cooperates with the leading edge of theupper plate to form a narrow gap therebetween through which a film unitis adapted to be advanced by the rollers.

In the operation of the camera disclosed in the above-referenced patent,the lower plate is maintained in the first position to block the passageof actinic light into the camera through the bit between the rollers. Afilm unit advancing through the rollers engages the lower plate andmoves it to the second position permitting the film unit to advancethrough the opening between the upper and lower plate. The spacingbetween the upper and lower plate is such that the portion of the filmunit forward of the film units trap may pass through the opening whilethe added thickness of the trap will prevent the trailing end of thefilm unit from passing through the opening until it is manually pulledthrough the space by the operator.

While the two plate film retainer performs quite well, it is relativelyexpensive to manufacture because of the dimensional tolerances requiredto ensure that the lower plate is accurately spaced from the upper platewhen it is in the second position. The opening formed by the upper andlower plate must be wide enough to permit the film unit to be advancedtherebetween so that both the upper and lower plate do not contact theimage-forming area of the film unit at the same time which may causemisalignment of the photosensitive and image-receiving elements and yetbe sufficiently narrow to prevent the trap at the trailing end of thefilm unit from passing through the opening. Also, the leading edges musthave a smooth finish to prevent scratching of the transparentimage-receiving element, thereby requiring an extra polishing ordeburring operation. Further, the film retainer is adapted to supportand retain only one film unit at a time.

The present invention provides a self-developing camera which is adaptedto automatically expose and process a film unit. The camera includesprocessing means in the form of a pair of juxtaposed pressure-applyingrollers of which at least one is power driven for engaging and advancingan exposed film unit along a film exit plane toward the exterior of thecamera while distributing a processing fluid contained therein over animage-forming area of the film unit. Film-engaging means, i.e., a filmretainer, is provided for engaging and supporting the exposed film unitonly along peripheral edges thereof which are outside of and formmargins surrounding the image-forming area. The film retainer includes afilm-supporting plate having an open portion therein through which thefilm unit is adapted to be partially advanced by the pressure-applyingrollers. The film-supporting plate is mounted for movement between afirst position in which the open portion is out of alignment with thefilm exit plane and the biteof the rollers to reduce the admission oflight into the camera via the bite, and a second position in which theopen portion is in alignment with the film exit plane to permit a filmunit to be advanced therethrough. The film retainer is spring biasedtoward the first position and is movable from the first position tothesecond position by a film unit advancing through the rollers and alongthe film exit plane. Two resilient fingers extend across opposite endsof the open portion of the film retainer and frictionally engage theperipheral edges of the film unit outside of the image-forming area tomaintain the film retainer in the second position against the bias ofthe spring urging the retainer toward the first position while allowingthe film unit to advance through the open portion. After the film unitpasses through the rollers, the resilient fingers cooperate withsurfaces on the film-supporting plate to arrest motion imparted to thefilm unit upon disengagement from the processing rollers and thereafterto releasably retain the film unit.

The. film retainer is adapted to support and releasably retain aplurality of film units. Provisions are made for totally disenabling theoperation of the camera when the number of film units supported by thefilm retainer reaches a predetermined limit or the angle of deflectionof the film retainer relative to the film exit plane reaches apredetermined angle. The relative spring gradients of the resilientfingers and the spring biasing the film retainer toward the firstposition are selected such that the second position or the position inwhich the film unit may pass through the open portion of the filmretainer is at a predetermined deplacement angle relative to the filmexit plane. The film retainer is configured and dimensioned such thatthe amount of frictional force applied to marginal edges outside of theimage-forming area of the film unit is dependent upon the relative anglebetween the film exit plane and the film retainer as the film unitpasses through the open portion. Upon disengagement of the film unitfrom the processing rollers, the biasing spring tends to move the filmretainer toward the first position rapidly changing the relative anglebetween the retainer and the film exit plane to apply maximum frictionalforce to peripheral edges outside of the image-forming area in a minimumamount of time.

Therefore, it is an object of the present invention to provide inphotographic apparatus including processing means for engaging andadvancing an exposed film unit along a'film exit plane toward theexterior of the apparatus while distributing a processing fluidcontained therein over an image-forming area of the film unit, and meansfor engaging and supporting the exposed film unit only along peripheraledges which form margins surrounding the image-forming area toreleasably retain the exposed film unit.

It is another object of the present invention to provide in photographicapparatus of the type including processing means for engaging andadvancing an ex posed film unit along a film exit plane, film-engagingmeans including a portion through which the exposed film unit is adaptedto be partially advanced by the processing means, and means engageableby the exposed film unit as the film unit is being advanced by theprocessing means for moving the film-engaging means between afirst'position in which the portion through which the film unit is aadapted to be partially advanced is out of alignment with the film exitplane, and a second position in which the portion is in alignment withthe film exit plane to permit the film unit to be advanced therethrough,first resilient means for biasing the film-engaging means towardsthefirst position and second resilient means for engaging the film unit insliding frictional engagement as the film unit is being advanced throughthe portion to maintain the film-supporting means in the second positionagainst the bias of the first resilient means and thereafter tocooperate with the portion to arrest motion imparted to the film unitupon disengagement from'the processing means and to releasably retainthe film unit.

It is the further object of the present invention to providephotographic apparatus of the foregoing type including film-engagingmeans adapted to support'a plurality of film units and means fordisenabling the operation of the apparatus when the number of film unitssupported by the film-engaging means exceeds a predetermined limit.

Another object of the present invention is to provide photographicapparatus of the aforementioned type wherein the film-engaging means ismounted for angular displacement relative to the film exit plane and themeans for disenabling the operation of the apparatus are actuable whenthe displacement angle exceeds a predetermined limit.

Other objects of the invention will in part be obvious and will in parthereinafter.

The invention accordingly comprises the apparatus possessing theconstruction, combination of elements, and arrangement of parts whichare exemplified in the following disclosure and the scope of theapplication of which will be indicated in the claims.

I BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of thenature and objects of the invention, reference should be had to thefollowing detailed description taken in connection with the accompanyingdrawings wherein:

FIG. 1 is an elevational view, partly in section, of a camera embodyingthe instant invention shown in an extended or operative configuration,and illustrating the relative positions of components of the camera to afilm unit located in position for exposure;

FIG. 2 is an elevational view taken along line 2-2 of the film retainerillustrating the placement of its component parts and its mounting onthe camera;

FIG. 3 is a perspective view of the camera of HG. 1 illustrating a filmunit advancing through pressure-applying rollers and in engagement witha film retainer;

FIGS. 4 through 7 are elevational views, partly in section, of thepressure-applying rollers and a film retainer illustrating theprogressive advancement of a film unit through the rollers and intoengagement with the film retainer showing the displacement angle of thefilm retainer relatively to the film exit plane;

FIG. 8 is an elevational view, partly in section, of the processingrollers and film retainer illustrating the displacement angle of thefilm retainer relative to the film exit plane while supporting two filmunits; and

FIGS. 9a, b, and c diagrammatically illustrate a means for disenablingthe operation of the camera when the film retainer supports apredetermined number of film units.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now toFIGS. l, 2 and 3of the drawings, a foldable, single-lens reflex camera of theself-developing type is shown generally at 10 in an extended andoperative configuration. The camera 10 includes a plurality of housingsections 12, 14, 16 and 18 which cooperate with bellows 22 (only oneside of which is shown) to form an exposure chamber 24 and a sectionextending forwardly of section 18. Housing sections l2, l4, and 16 areadapted to pivot about axes 13, 15, 17 and 19 for movement between theextended position, as shown in FIG.'1, and a compact folded position. Tofold camera 10, housing section 12 is rotated in a clockwise directioninto the forward portion of housing section 20 with housing sections 14and 16 forming a planar outer surface over a portion of housings 12 and18, respectively. As camera 10 is folded, the bellows 22 collapses alongmemory lines 26 and is stored between the upper and lower housingsections.

Housing section 18 includes a chamber 28 for receiving and supporting afilm container 30 preloaded with a plurality of film units 32 in stackedrelation. The film container 30, as best shown in FIG. 1, includes aforward wall 34 having an integrally formed upstanding rib 36 whichdefines a generally rectangular aperture 38 through which light isadmitted to expose the forwardmost film unit 32 contained therein.Upstanding rib 36 is adapted to be telescopically received by an opening60 located in a support frame 58 for properly locating the forwardmostfilm unit 32 in position for exposure. Film container 30 furtherincludes a leading end wall 40 having an elongated rectangular exitopening 42 therein through which a film unit is adapted to be movedsubsequent to exposure, a flexible opaque sheet 43 covering exit opening42 to block the passage of actinic light into the film container throughexit opening 42, and a rear wall 64 adapted to be engaged by a spring 62for urging the film container 30 toward support frame 58.

Each of the individual film units 32 includes: a photosensitive element44; a superposed transparent image-receiving element 46; a pod 48containing a viscous processing fluid joined to elements 44 and 46 at aleading end of the film unit; a fluid reservoir or trap 50 formed at thetrailing end of the film unit; and an opaque binding element forsecuring the photosensitive element 44 and the image-receiving element46 in faceto-face relation and also forming opaque peripheral margins onthe transparent image-receiving element including lateral margins 52 andlongitudinal margins 54 which define the bounds of a substantiallyrectangular image-forming area 56 as best shown in FIG. 3.

Pod 48 is adapted to rupture upon the application of compressivepressure, thereby releasing the viscous processing fluid which is spreadbetween and in contact with elements 44 and 46 in a thin uniform layercovering the image-forming area 56 toinitiate the development of filmunit 32, as described in detail in U.S. Pat.

No. 3,415,644, granted on Dec. 10, 1968, to E. H.

Land and assigned to the same assignee as the instant invention.

Film units 32 are preloaded into film container 30 in stacked relationand are spring biased, by means not shown, toward forward wall 34. Thefilm units 32 are positioned so that the transparent image-receivingelement 46 faces toward the exposure aperture 38 which is substantiallyco-extensive with the image-forming area 56 of the film unit. Theforwardmost film unit 32 is adapted to be exposed through exposureaperture 38 and then removed from the film container via exit openingfor processing. A rectangular slot not shown) in forward wall 34provides access to the forwardmost film unit for removing it from thefilm con tainer. An opaque sheet not shown covering all of the aperturesin film container 30 is initially provided within the film container toprevent exposure of the film units prior to insertion of the filmcontainer into the camera and is removable in the same manner as theforwardmost film unit once the film container is loaded into receivingchamber 28.

Access to receiving chamber 28 for loading or unloading a film containeris provided by pivotally connecting housing section 20 to housingsection 18 for movement in a clockwise direction from the operativeposition as shown in FIG. 1', thereby exposing an open end of chamber 28through which the film container may be inserted or withdrawn. Fordetails as to the construction of the receiving chamber 28 and thecoupling and movement of housing section 20, reference may be' had toU.S. patent application Ser. No. 102,775, filed on Dec. 30, l970.

Camera 10, being of the single-lens reflex variety, is adapted to beoperated first in a viewing and focusing mode and then in an exposuremode. A platelike reflex member 66, as shown in solid lines in FIG. 1 inits viewing and focusing position atop support member 58 and upstandingrib 36 covering apertures 38 and 60, forms a lighttight barrier betweenexposure chamber 24 and the receiving chamber 28, and includes anechelontype mirror 68 on one side and a planar mirror 70 on the oppositeside. Reflex member 66 which is adapted to pivot about axis 71 is springbiased for movement toward housing section 16 and is held in the viewingand focusing position by a latching member not shown).

In the viewing and focusing mode of operation, light rays reflected fromthe scene to be photographed pass through an objective lens 72, mountedin housing section 12', and travel cross exposure chamber 24 until theyimpinge upon a planar mirror 74, fixedly mounted on an interior watt ofhousing section 16, and are then reflected toward echelon-type mirror.68 where they form an image of the scene to be photographed. From mirror68 the light rays are redirected toward a suitable viewfinder not shown)mounted on housing section 14. The operator views the image at mirror 68through the viewfinder while adjusting objective lens 72 until the imageis in sharp focus and then actuates a shutter release button 76 mountedon housing section 12.

Actuation of button 76 closes a normally open switch energizing anelectronic exposure control circuit shown diagrammatically at 78 inhousing section 12 which is adapted to sequentially energize andde-energize electronic components within the camera including a motor 80mounted in the trailing end of housing section 18 during an exposure andprocessing cycle. Energy is supplied to exposure control circuit 78 by abattery which may be suitably mounted within camera or may be providedwithin film container 30 to insure that there will be sufficient energyto expose and process all of the film units contained within the filmcontainer each time thata new film container is loaded into the camera.4 4

Upon actuationof button 76, exposure control circuit 78energizesnormally open shutter means not shown) causing the shuttermeans to move position blocking the passage of light into chamber 24through lens 72 and the viewfinder is conditioned to prevent entry oflight into chamber 24. Once chamber 24 is in a lighttight condition,reflex member 66 is unlatched, either electronically or mechanically, inresponse to movement of linkage driven by motor 80 and moves under theinfluence of the biasing spring to an exposure position parallel withand closely adjacent to fixed mirror 74, as shown in phantom lines inFIG. 1, with planar mirror 70 facing toward objective lens 72. Theshutter means blocking objective lens 72 is then de-energized causingthem to move to an unblocking position permitting light rays to strikemirror 70 from where they are reflected through exposure aperture 38 toexpose the forwardmost film unit 32. After an appropriate exposureinterval, the shutter means are again energized causing them to move toa position blocking passage of light through objective lens 72. Motor 80which is coupled to reflex member 66 by suitable linkage is energized todrive reflex member 66 from the exposure position against the bias ofthe spring to the viewing and focusing position and into engagement withthe latching member and the shutter means are de-energized. At the sametime, motor 80 drives a filmadvancing mechanism, positionable throughthe aperture in forward wall 34 of the film container, to engage theexposed forwardmost film unit 32 and advance it through exit opening 42into the bite of a pair of juxtaposed pressure-applying rollers 82 and84.

The upper roller 82 is mounted in a fixed position and the lower roller84 is mounted for vertical displacement relative to roller 82 and isspring biased upwardly with a suitable stop being provided to maintain apredetermined spaceor gap between the two pressureapplying rollers.Roller 82 is adapted to be rotatably driven, by suitable transmissionmeans coupled to motor 80, in a counterclockwise direction to advancethe exposed film unit along a film exit plane which containsthe gapbetween the pressure-applying rollers and is substantially perpendicularto a plane containing the film unit passes between the rollers, roller84 moves downwardly against the bias of the spring to accommodate thethickness of the fluid containing pod 48. The rollers apply acompressive pressure to the pod causing it to rupture, thereby releasingthe viscous processing fluid. Upon release of the fluid, the podcollapses and the lower roller 84 moves upwardly to maintain thepredetermined spacing between the rollers. The rollers spread theprocessing fluid in a thin, uniform layer between and in contact withthe photosensitive element 44 and the image-receiving element 46 withthe predetermined spacing between the rollers controlling the thicknessof the ayer of fluid. The film unit is advanced at a constant rate,approximately seven inches per second, spreading the processing fluidover the image-forming area 56 of the film unit with any excess fluidbeing deposited in the fluid reservoir or trap 50 at the trailing end ofthe film unit. it will be noted that the fluid reservoir or trap 50 isthicker than that portion of the film unit extending forwardly of thetrap,.and as the trap is engaged in the bite between rollers 82 nd 84,the lower roller 84 is moved downwardly allowing the trap to passbetween the rollers, and then abruptlyv moves upwardly toward the upperroller 82 under the influence of the biasing spring tending to nip thetrailing edge of the film unit which increases its forward velocity.Once the film unit has passed through'the rollers, the electroniccontrol circuit 78 de-energizes motor 80, thereby completing theexposure and processing cycle. For details as to the sequentialfunctioning of the electronic control circuit 78, reference may be hadto U.S. patent application Ser. No. 68,919, filed on Sept. 2, 1970, andassigned to the same assignee as the present invention.

As the leading end of the exposed film unit passes from between rollers82 and 84, it engages a film retainer 86 located outboard of rollers 82and 84. F ilm retainer 86, see FIG. 2., includes a thin, elongated filmsupport plate 88, laterally dimensioned to extend across the length ofpressure-applying rollers 82 and 84, having four integrally formed,rearwardly extending mounting flanges 90. Each flange 90 has a mountinghole therein through which a mounting axle 92 is inserted for pivotallymounting plate 88 on the exit side of the pressure-applying rollers. Apair of helically wound springs 94, circumscribing axle 92, each havingone end secured to structure supporting the pressureapplying rollers andthe opposite end secured to plate 88, are provided for spring biasingthe film retainer 86 toward the upright position as shown in FIGS. 1 and4. Film support plate 88 further includes a pair of film-engaging arms96 extending upwardly and inwardly from a horizontal edge 98 at theupper portion of plate 88 which form openings 100 therebetween throughwhich a film unit is adapted to be advanced. It will be noted thatfilm-engaging arms 96 are dimensioned so as to only overlie the lateralmargins 52 of the film unit as it is advanced through openings 100. Apair of resilient fingers 102 are secured to the bottom portion of plate88 and extend upwardly and in covering relation to the openings 100between the film-engaging arms 96 and the horizontal edge 98.

Referring now to FIGS. 4-8, for purposes of illustration, a base line85, substantially parallel to the film exit plane, is provided to showthe relative angle between film retainer 86 and the film;exit plane. Asbest shown in FIG. 4, the biasing springs 94 maintain film retainer 86in an upright position substantially perpendicular to the film exitplane with horizontal edge 98 positioned above the space or gap betweenthe pressure-applying rollers so that openings 100 are out of alignmentwith the film exit plane. In this position, film retainer 86 functionsas a light barrier blocking the passage of actinic light through thespace between the pressure-appling rollers which may cause the foggingof a film unit which. has been advanced through exit ,opening 42 of thefilm container but has not as yet advanced far enough so that theleading edge of the film unit is in engagement with thepressure-applying rollers. The angle between the film retainer 86 in theblocking position and the film exit plane is denoted as 0,.

Asthe film unit is advanced through the rollers, the leading edge of thefilm unit engages plate 88 below horizontal edge 98 causing filmretainer 86 to rotate in a clockwise direction until openings 100 are inalignment with the film exit plane at a displacement angle of 0 denotingalignment, thereby permitting the leading edge of the film unit to passthrough openings 100 and into engagement with resilient fingers 102 asshown in FIG. 5. The relative spring gradients are selected such thatthe resilient fingers 102 have a lower spring gradient or springconstant than the biasing springs 94. As the film unit continues toadvance through openings 100, the resilient fingers 102 deflect as shownin FIGS. 5, 6, and 7 and engage the lateral margins 52 on the undersideof the film unit 32 in sliding frictional engagement. It will be notedthat by properly selecting the relative spring gradients of biasingsprings 94 and resilient fingers 102, it is possible to maintain filmretainer 86 at a predetermined angle 0,, against the bias of springs 94when a film unit is in engagement with the fingers 102 and beingadvanced through openings 100 by rollers 82 and 84. As the film unit 32is further advanced through openings 100 in sliding frictionalengagement with resilient fingers 102, the fingers 102 lift the filmunit 32 above edge 98 as best shown in FIG. 6 so that edge 98 does notcontact the underside of the image-forming area 56. Upon disengagementof the trailing end of the film unit 32 from the pressure-applyingrollers, the film unit rotates in a clockwise direction about the areaof contact between the marginal edges 52 on the underside of the filmunit and the resilient fingers 102 due to the weight of the film unitextending forwardly of the resilient fingers, causing the lateralmargins 52 on the upper surface of the film unit 32 to move into slidingfrictional engagement with film-engaging arms 96. The combinedfrictional forces applied to lateral margins 52 by the resilient fingers102 and the film-engaging arms 96 are sufficient to arrest the motionimparted to the film unit upon disengagement from the pressure-applyingrollers and thereafter to advancing film unit by the film retainer 86 isa function of the angle formed between the portion of the film unitlocated in the film exit plane and the film retainer. For example, inFIG. 6, the film unit and the film retainer form an obtuse angletherebetween with resilient fingers 102 being the only component of thefilm retainer 86in engagement with the lateral margins 52. As best seenin FIG. 7, when the film unit 32 and the film retainer 86 form an acuteangle therebetween, the resilient fingers 102 are further deflected,applying a greater frictional force to lateral margins 52 and,additionally, film-engaging arms 96 are in engagement with the upperlateral margins 52.

Once the film unit 32 has been disengaged from the pressure-applyingrollers, it is desirable to change the angle between the film unit 32and the film retainer 86 as rapidly as possible to counteract theforward momentum of the film unit 32 by applying maximum frictionalforce to the film unit. In addition to the clockwise rotation of thefilm unit due to the weight of that portion of the film unit forward ofresilient fingers 102, the biasing springs 94 rotate the film retainer86 in a counterclockwise directiontoward the blocking position whichalso aids in rapidly changing the angle between the film retainer 86 andthe film unit 32.

As best shown in FIG. 3, the advancing film unit extends beyond theleading edge of housing section 20 and is retained in a position, asbest shown in FIG. 7, with the trailing end of the film unit inengagement with film retainer 86 and a portion of the film unit forwardof the trailing end resting on the leading edge of housing section 20.It will be noted that the weight of one retained film unit counteractsthe counterclockwise bias of springs 94 so that the film retainer 86 ismain tained at a displacement angle of 0, denoting one retained filmunit, which is intermediate angles 6,, and 0 It will be noted that theretained film unit in FIG. 7 is 'maintained at an acute angle relativeto the film retainer 86 and is positioned so as to be in closingrelation with the bite between rollers 82 and 84 acting as a lightbarrier to prevent actinic light from passing between thepressure-applying rollers. Should the operator of the camera actuateshutter release button 76 to initiate a second exposure and processingcycle, a second film unit, shown in phantom lines in FIG. 7, passingbetween the rollers may pass through openings and into engagement withresilient fingers 102 so as to be supported in and retained in aposition underlying the first retained film unit as shown in FIG. 8. Itwill be noted that the combined weight of the two retained film unitscauses film retainer 86 to be maintained at a displacement angle of 0denoting two retained film units, which is smaller than angle 0,, or,more accurately, a position of maximum displacement relative to theblocking position of 0 As a safety precaution, means may be provided fordisenabling the operation of the camera when a predetermined number offilm units are supported by the film retainer 86, or when the angulardisplacement angle 0 of film retainer 86 exceeds a predetermined limit.For example, FIGS. 4-8 illustrate a method for film units are supportedand retained by film retainer 86. A pair of normally closed electricalcontacts 104 are connected in series to the normally open switch inelectronic control circuit 78 which is adapted to be closed uponactuation of shutter release button 76. One contact is mounted on afixed support member 106, the second contact is mounted on a resilientsupport member 108 which extends into the path of travel of mountingflange 90. It will be noted that flange 90 does not engage supportmember 108 until the film retainer 86 is displaced at an angle 0,, whichin turn is a function of the combined weights of the two retained filmunits where it deflects support member- 108 in a clockwise direction,thereby opening contacts 104 which in turn disenables electronic controlcircuit 78. Removal of the two retained film units will cause filmretainer 86 to rotate in a counterclockwise direction permitting member108 to return to the position shown in FIGS. 4, 5, 6 and 7, therebyclosing contacts 104.

An alternative method of disenabling the operation of camera 10 whenonly one film unit is supported by film retainer 86 is diagrammaticallyillustrated in FIGS.

counterclockwise direction (see FIG. 90) opening the two normally closedcontacts 104, thereby disenabling control circuit 78. Removal of theretained film unit permits bias spring 94 to rotate film retainer 86toward the blocking position with sufficient force to disengage arm 110from support member 112, thereby allowing contacts 104 to" return totheir normally closed position.

SUMMARYOF THE INVENTION From the foregoing it can be seen that there hasbeen disclosed photographic apparatus of the type including processingmeans for engaging and advancing an exposed film unit along a film exitplane toward the exterior of the apparatus while distributing aprocessing fluid across an image-forming area of the film unit andfilm-engaging means for engaging and supporting at least one exposedfilm unit only at peripheral edges thereof which form marginssurrounding the imageforming area of the film unit to releasably retainthe exposed film unit. The film-engaging means include a portion throughwhich the film unit is adapted to be partially advanced by theprocessing means and includes means engageable by the film unit as it isadvanced by the processing means for moving the filmengaging meansbetween a first position in which the portion is out of alignment withthe film exit plane and a second position in which a portion is inalignment with the film exit plane to permit a film unit to be advancedtherethrough. First resilient means are provided for biasing thefilm-engaging means toward the first position and second resilient meansadapted to engage the film unit in sliding frictional engagement as thefilm unit is advanced through the portion are provided to maintain thefilm-engaging means in the second position against the bias of the firstresilient means and thereafter the second resilient means cooperate withthe portion to arrest motion imparted to the film unit upondisengagement from the processing means and to releasably retain thefilm unit. The photographic apparatus also includes means fordisenabling operation of the apparatus when the number of film unitssupported by the film-engaging means exceeded a predetermined limit. I

Since certain changes may be made in the above apparatus withoutdeparting from the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

What is claimed is:

1. Photographic apparatus comprising:

processing means for engaging and advancing an exposed film unit along afilm exit plane toward the exterior of said apparatus while distributinga processing fluid across an image-forming areaof the film unit; andfilm engaging means for selectively engaging and supporting at leastone' film unit only along peripheral edges thereof which form marginssurrounding the image-forming area as the film unit is advanced alongthe film exit plane by said processing means and for arresting themotion of the film unit upon its disengagement from said processingmeans to releasably retain the film unit on said apparatus.

2. Photographic apparatus as defined in claim 1 further including meansfor disenabling the operation of said apparatus when the number of filmunits sup ported by said film-engaging means exceeds a predeterminedlimit. a

3. Photographic apparatus as defined in claim wherein said predeterminedlimit is more than one film unit.

4. Photographic apparatus as defined in claim 1 wherein said filmengaging means includes a plate having an open portion therein throughwhich the film unit is adapted to be partially advanced by saidprocessing means, said plate further including a pair of film engagingarms for selectively engaging lateral margins of the film unit when thefilm unit is disengaged from said processing means to releasably securethe film unit to said plate.

5. Photographic apparatus as defined in claim 4 wherein said filmengaging means is adapted to releasably retain more than one film unitat a time on said apparatus.

6. Photographic apparatus comprising:

processing means for engaging and advancing an exposed film unit along afilm exit plane toward the exterior of said apparatus while distributinga processing fluid across an image-forming area of the film unit;

film-engaging means for engaging and supporting at least one exposedfilm unit only along peripheral edges thereof which form marginssurrounding the image-forming area of the film unit to releasably retainthe exposed film unit;

means for mounting film-engaging means for angular displacement relativeto said film exit plane, said displacement angle being determined by thenumber of film units supported by said film-engaging means; and a meansfor disenabling the operation of said apparatus when said displacementangle exceeds a predetermined limit and the number of film unitssupported by said film-engaging means required to exceed saidpredetermined limit is more than one.

7. Photographic apparatus comprising:

processing means for engaging and advancing a film unit along a filmexit plane;

film-engaging means including a portion through which the film unit isadapted to be partially ad vanced by said processing means and meansengageable by the film unit as the film unit is being advanced by saidprocessing means for moving said film-engaging means between a firstposition in which said portion is out of alignment with said film exitplane and a second position in which said portion is in alignment withsaid film exit plane to permit the film unit to be advancedtherethrough;

first resilient means for biasing said film-engaging means toward saidfirst position; and y second resilient means for engaging the film unitin sliding frictional engagement as the film unit is being advancedthrough said portion to maintain said film-engaging means in said secondposition against the bias of said first resilient means and thereafterto cooperate with said portion to arrest motion imparted to the filmunit upon disengagement from said processing means and to releasablyretain the film unit.

8. Photographic apparatus as. defined in claim 7 wherein saidfilm-engaging means is mounted for angular displacement relative to saidfilm exit plane and the relative spring gradients of said first andsecond resilient means are selected so that said second position is at apredetermined displacement angle.

9. Photographic apparatus as defined in claim 8 wherein the springgradient of said second resilient means is lower than the springgradient of said first resilient means.

l0. Photographic apparatus as defined in claim 8 wherein said portionand saidsecond resilient means apply a frictional force to the film unitto arrest motion and releasably retain the film unit upon disengagementthereof from said-processing means.

11. Photographic apparatus as defined in claim 10 wherein the amount offrictional force is dependent on the relative angle between the filmunit and said filmengaging means as the film unit moves through saidportion.

12. Photographic apparatus as defined in claim 11 wherein, upondisengagement of the film unit from said processing means, said firstresilient means moves said film-engaging means toward said firstposition, thereby rapidly changing the relative angle between saidfilmengaging means and the film unit to apply maximum frictional forceto the film unit.

13. Photographic apparatus as defined in claim 7 wherein saidfilm-engaging means reduces admission of light into said apparatus whenin said first position.

1. Photographic apparatus comprising: processing means for engaging andadvancing an exposed film unit along a film exit plane toward theexterior of said apparatus while distributing a processing fluid acrossan image-forming area of the film unit; and film engaging means forselectively engaging and supporting at least one film unit only alongperipheral edges thereof which form margins surrounding theimage-forming area as the film unit is advanced along the film exitplane by said processing means and for arresting the motion of the filmunit upon its disengagemEnt from said processing means to releasablyretain the film unit on said apparatus.
 2. Photographic apparatus asdefined in claim 1 further including means for disenabling the operationof said apparatus when the number of film units supported by saidfilm-engaging means exceeds a predetermined limit.
 3. Photographicapparatus as defined in claim wherein said predetermined limit is morethan one film unit.
 4. Photographic apparatus as defined in claim 1wherein said film engaging means includes a plate having an open portiontherein through which the film unit is adapted to be partially advancedby said processing means, said plate further including a pair of filmengaging arms for selectively engaging lateral margins of the film unitwhen the film unit is disengaged from said processing means toreleasably secure the film unit to said plate.
 5. Photographic apparatusas defined in claim 4 wherein said film engaging means is adapted toreleasably retain more than one film unit at a time on said apparatus.6. Photographic apparatus comprising: processing means for engaging andadvancing an exposed film unit along a film exit plane toward theexterior of said apparatus while distributing a processing fluid acrossan image-forming area of the film unit; film-engaging means for engagingand supporting at least one exposed film unit only along peripheraledges thereof which form margins surrounding the image-forming area ofthe film unit to releasably retain the exposed film unit; means formounting said film-engaging means for angular displacement relative tosaid film exit plane, said displacement angle being determined by thenumber of film units supported by said film-engaging means; and meansfor disenabling the operation of said apparatus when said displacementangle exceeds a predetermined limit and the number of film unitssupported by said film-engaging means required to exceed saidpredetermined limit is more than one.
 7. Photographic apparatuscomprising: processing means for engaging and advancing a film unitalong a film exit plane; film-engaging means including a portion throughwhich the film unit is adapted to be partially advanced by saidprocessing means and means engageable by the film unit as the film unitis being advanced by said processing means for moving said film-engagingmeans between a first position in which said portion is out of alignmentwith said film exit plane and a second position in which said portion isin alignment with said film exit plane to permit the film unit to beadvanced therethrough; first resilient means for biasing saidfilm-engaging means toward said first position; and second resilientmeans for engaging the film unit in sliding frictional engagement as thefilm unit is being advanced through said portion to maintain saidfilm-engaging means in said second position against the bias of saidfirst resilient means and thereafter to cooperate with said portion toarrest motion imparted to the film unit upon disengagement from saidprocessing means and to releasably retain the film unit.
 8. Photographicapparatus as defined in claim 7 wherein said film-engaging means ismounted for angular displacement relative to said film exit plane andthe relative spring gradients of said first and second resilient meansare selected so that said second position is at a predetermineddisplacement angle.
 9. Photographic apparatus as defined in claim 8wherein the spring gradient of said second resilient means is lower thanthe spring gradient of said first resilient means.
 10. Photographicapparatus as defined in claim 8 wherein said portion and said secondresilient means apply a frictional force to the film unit to arrestmotion and releasably retain the film unit upon disengagement thereoffrom said processing means.
 11. Photographic apparatus as defined inclaim 10 wherein the amount of frictional force is dependent on therelative angle between the film unit and said film-engaginG means as thefilm unit moves through said portion.
 12. Photographic apparatus asdefined in claim 11 wherein, upon disengagement of the film unit fromsaid processing means, said first resilient means moves saidfilm-engaging means toward said first position, thereby rapidly changingthe relative angle between said film-engaging means and the film unit toapply maximum frictional force to the film unit.
 13. Photographicapparatus as defined in claim 7 wherein said film-engaging means reducesadmission of light into said apparatus when in said first position.